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Anusuya Rangarajan

Both growers and vegetable seed companies have had long-term historic relationships with public agriculture extension educators and faculty to conduct unbiased evaluation of vegetable varieties. Reductions in both the number of vegetable seed companies as well as university human resources has led to questions about the viability and appropriateness of publicly-funded variety evaluation programs. Field based extension educators and regional staff have taken more leadership to evaluate varieties, but this often results in fragmented or repetitive trials with limited long term integration of data. Statewide vegetable extension specialists must provide the leadership in coordinating these trials to enhance the rigor of data collection and analysis. Fundamental to enhancing rigor is improving regional coordination and collaboration. The calculation of stability estimates for new and older varieties is most efficiently and quickly achieved through regional collaborations. Initial efforts should improve uniformity of trials by creating common evaluation methods for yield and qualitative evaluations (e.g., color, appearance), including two standard varieties (one local and one regional, long-term standard), standardizing field establishment practices, and selecting experimental designs and plot sizes to improve labor efficiency. These regionally coordinated trials will improve the ability to publish this type of applied research and demonstrate new levels of efficiency for university administrations. In the long term, carefully designed comparisons of genotypic performance among different environments could suggest new directions for university breeding programs as well as cropping systems research.

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David Conner and Anusuya Rangarajan

The market premiums that currently exist for many organic crops are an attractive incentive for conventional growers considering the transition to organic practices. Before making this decision, there is a need to better understand the production costs of these systems. While many factors, such as crop rotation, soil type, and marketing, influence cropping decisions, production costs are vital information for production and pricing decisions. This research evaluated crop budgets from two Pennsylvania organic farms as case studies. A critical component of these budgets was the calculation of costs related to cover cropping, rotations, and compost production or use. These farms were very different in their scale, management, and marketing strategies. The crops selected for study on each farm were also different, based upon economic value to the farm. Beech Grove Farm used horse traction and hired no production labor on about 4 acres of production; budgets for carrot (Daucus carota), onion (Allium cepa), and garlic (Allium sativum) are presented. The other, Spiral Path Farm, used machinery and a hired labor crew extensively on about 60 acres; their production costs for tomato (Solanum lycopersicum), lettuce (Lactuca sativa), and winter squash (Cucurbita moschata) are presented. While costs could not be compared between the farms, costs per acre varied widely among crops on a farm, but less so across years. Neither farm spent a great deal on pest control inputs, relying on soil fertility and other management practices to minimize infestations and grow healthy plants. While these single-crop budgets provided some realistic measures of costs of organic vegetable production, longer-term budgets measuring multiyear rotations would better capture the tradeoffs made by diversified organic farmers.

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Anusuya Rangarajan and Betsy Ingall

Interest in the production of the specialty vegetable radicchio (Cichorium intybus L. var. silvestre Bisch.) has increased among vegetable growers in the northeastern United States due to the popularity and consumption of premixed prepared salads. Growing environments with moderate daytime temperature and high light level have been associated with dense, deep red heads. Production problems include the low percentage of plants producing marketable heads and labor costs associated with hand-weeding. Traditional bareground culture was compared with several colored mulches (white, silver, red, black, and blue) for their effects on head formation, size, yield, and color of two Italian cultivars. Field studies were conducted in Freeville (upstate), N.Y., in 1997 and 1998. The percentage of heads harvested ranged from 32% to 82% over the 2 years of experiments and was lowest in black and red plastic mulch treatments. Yields were significantly higher, heads larger, and harvest earlier for plants grown over silver and white mulch compared to the control and other mulch treatments in 1998. In addition, average head weight was greater in all mulch treatments except blue when compared with the control. Cultivar differences were measured for the number and weight of heads, the percent bolting and marketable heads, and head color in 1998. Air and soil temperatures varied significantly around these mulches; however, these differences in microclimate had no effect on head color quality. Despite relatively moderate temperatures in upstate New York, radicchio responded positively to mulches that lowered average soil temperatures (white and silver) compared with the other treatments.

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Kamyar Aram and Anusuya Rangarajan

Two types of commercial compost produced from manure and food waste or brewery waste solids were tested for supplying the N requirements of a bell pepper crop in a drip-irrigated plasticulture system over two seasons. Composts were tested at 40 and 80 Mg·ha-1, and combined with 67 and 133 or 0 and 67 kg·ha–1 N applied as mineral fertilizer in the first and second seasons, respectively. Both types of compost increased total soil carbon and N content relative to unamended soil. Compost amendment also increased soil NO3-N, NH4-N and N mineralization potential throughout the season, but yields were not affected. Increasing compost amendment rate from 40 to 80 Mg·ha–1 did not increase N levels in soil or plants. Yield was not affected and season biomass accumulation was inconsistently affected by compost amendment. Commercial composts thus released mineral N in the first year of application, but supplementation with mineral fertilizer may be necessary depending on seasonal variation of N release and crop need.

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Anusuya Rangarajan and Betsy A. Ingall

Annual production of globe artichokes (Cynara scolymus L.) requires vernalization of the plants, either through cold treatment of transplants or from natural temperature conditions in the spring. Studies were conducted in upstate New York to determine if artificial vernalization treatments could be achieved by earlier planting dates. Initial trials evaluated two cultivars used for annual production in other parts of the country—'Imperial Star' and `Green Globe Improved'. Transplants were set in the field with or without a vernalizing cool treatment, to determine the extent of natural vernalization achieved under New York conditions. `Imperial Star' produced slightly higher marketable yields than `Green Globe Improved' in 2 years of trials. Vernalization treatment increased the number of plants producing buds and the marketable yields, when transplants were set after 15 May. Natural vernalization was achieved and cold treatment prior to transplanting did not improve yields of plants established in early May. At later planting dates, vernalizing transplants increased the number of plants producing apical buds (largest) by about 20%, yet, >57% of non-vernalized plants of each variety produced buds within the season. Average bud sizes did not vary with vernalization treatment. A similar number of days from transplanting to first bud harvest (69 to 75) was noted regardless of planting date and size of transplant.

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Anusuya Rangarajan and John F. Kelly

Over the past few years, studies have been conducted exploring the variability in iron nutritional quality from a tropical vegetable, Amaranthus. In order to confirm previous iron bioavailability data, A. cruentus, A. hypochondriacus and A. tricolor lines were grown at the MSU Horticulture Research Center and then analyzed for total and in vitro bioavailable iron. Leaves were harvested 39 days after transplanting, washed, lyophilized and ground. Total iron levels were determined using atomic absorption spectroscopy and bioavailable iron estimates derived using an in vitro assay simulating gastrointestinal digestion. Among the lines tested, total iron concentrations ranged from 145 to 506 ppm. Bioavailable iron ranged from 44 to 70 ppm. Both the total and bioavailable iron measured were highest in A. tricolor, similar to results of previous years. Total iron values were lower for all of the lines than detected previously, but the range of bioavailable iron was similar to earlier work. Bioavailable iron estimated using the in vitro procedure does not appear to be greatly influenced by fluctuations in total iron content. Amaranth could provide between 44 and 70 mg Fe/100 gm fresh weight, equal to 20-35% of the daily Fe requirement for women, and 40-70% for men. Future experiments will utilize an animal bioassay to verify differences detected in bioavailable iron.

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Anusuya Rangarajan and Theodore W. Tibbitts

Oedema, a physiological disorder, affects several cultivars of ivy geranium [Pelargonium peltatum (L.) L `Hér. ex Ait) when grown in greenhouses. This study investigated the regulation of oedema on this crop using far-red radiation because these wavelengths inhibited the injury on Solanaceous sp. Plants were exposed to far-red radiation from Sylvania #232 far-red lamps on abaxial and adaxial surfaces of leaves. A far-red photon flux of 15 to 20 μmol·m-2·s-1 (700-S00 nm) was not effective in preventing oedema injury. A far-red abaxial treatment during the light period tended to reduce the amount of injury that developed when photosynthetic photon flux was low (130-170 μmol·m-2·s-1), but this inhibition of the injury was absent with higher photon flux. The results from these studies indicate the use of supplemental far-red radiation treatments in greenhouses would not be justified because adequate and consistent control of the injury on ivy geraniums was not achieved.

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Robert B. Gravani, Anusuya Rangarajan and Elizabeth Bihn

The 1998 Fresh Trends Survey, conducted by “The Packer,” indicated that about 60% of consumers are more concerned today, than 1 year ago, about Salmonella, E. coli 0157:H7, and other bacteria on fresh produce. Since 1987, the number of produce-associated outbreaks has doubled, affecting twice as many people, and involving a variety of fruits and vegetables. Three quarters of these outbreaks (75%) were associated with domestically grown produce. In recent months, as several large grocery chains have informed their produce suppliers that growers must have a certified plan for the farm that focuses on reducing risks for microbial contamination, to continue supplying fruits and vegetables. These actions have caused extreme concern among fruit and vegetable producers. A comprehensive educational curriculum has been developed for growers and shippers focused on recommended “Good Agricultural Practices.” This effort is the result of an extensive collaborative project, involving researchers, extension educators, and grower organizations nationwide. The curriculum sections include the history of foodborne illness associated with produce, the basic principles of food microbiology, recommended good agricultural practices to reduce risks of contamination due to irrigation water, wild and domestic animals, manure, and farm workers hygiene, resources for training employees, farm assessment worksheets, and other information resources. These educational materials and visuals will be made available on CD-ROM in the near future.

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Anusuya Rangarajan, A. Raymond Miller and Richard Veilleux

Leptine (LP) glycoalkaloids have been demonstrated to confer natural resistance to the Colorado potato beetle (CPB) in Solanum chacoense (chc). Development of cultivated potatoes with natural resistance to CPB has the potential to reduce both costs and environmental impacts of production by reducing pesticide use. To introgress the genes conferring leptine production from chc into S. tuberosum (tbr), clones of chc have been crossed with clones of S. phureja. Leaf disks from eight hybrids were subjected to a CPB second instar feeding bioassay to determine if extent of feeding was related to LP levels. Most hybrids contained leptinidine (LD, the aglycone of LP) levels intermediate to chc and tbr, and insect feeding was suppressed 30% to 50% in hybrids containing >10 mg·g–1 DW LD. One hybrid displaying feeding suppression contained a very low level of LD, whereas another hybrid that contained higher levels of LD had higher feeding rates. The presence of LD at “threshold” levels in these hybrids will suppress feeding of CPB, but other factors affecting resistance are also present and need to be explored.

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Anusuya Rangarajan, Betsy A. Ingall, Michael D. Orzolek and Lewis Otjen

Butternut squash (Cucurbita moschata) plants are susceptible to defoliation and plant population (stand) reduction by insect, disease, temperature extremes, water, hail, or other mechanical damage. The timing of such losses may have variable effects on final fruit quality and yield. The objectives of these studies were 1) to determine the influence of the degree and timing of defoliation and stand reduction on the marketable yield of winter squash; 2) to determine yield compensation after stand reduction and defoliation; and 3) to explore effects of defoliation on fruit total carotenoid content. Experiments were conducted over 2 years in New York and Pennsylvania to explore these objectives. Marketable yields consistently improved with increasing plant population. If population losses occurred while plants were in the rapid vegetative growth phase, the remaining plants responded by increasing fruit number and weight per plant. Plant losses later in the season during fruit enlargement, however, did not elicit the same magnitude of response. Defoliation of 66% leaf area reduced marketable yields, and effects were most severe under high plant populations. Competition among plants restricted compensation. Moderate defoliation (33%) reduced yield in only one of three studies. This level of defoliation also increased the percentage of medium [1.0 to 1.5 kg (2.20 to 3.31 lb)] and large [1.5 to 2.0 kg (4.41 lb)] fruit and decreased the number of jumbo fruit (>2.0 kg). Total carotenoid concentration in mature fruit was unaffected by the defoliation or population treatments. Thus, butternut squash compensated for up to 33% leaf area loss at any time during the season. While the crop could compensate, under some conditions, for up to 50% plant losses, final plant population was more important than the growth stage of damage or defoliation for effects on crop yield.